Knock

"Though Orientals are very jealous of their privacy, they never knock when about to enter your room, but walk in without warning or ceremony. It is nearly impossible to teach an Arab servant to knock at your door. They give warning at the outer gate either by calling or knocking. To stand and call is a very common and respectful mode. Thus Moses commanded the holder of a pledge to stand without and call to the owner to come forth ( Deuteronomy 24:10 ). This was to avoid the violent intrusion of cruel creditors. Peter stood knocking at the outer door ( Acts 12:13Acts 12:16 ), and the three men sent to Joppa by Cornelius made inquiry and 'stood before the gate' ( Acts 10:17Acts 10:18 ). The idea is that the guard over your privacy is to be placed at the entrance."

The oriental house was fitted with heavy doors which were bolted and locked with wooden keys too large to be carried about, so that even a member of the household could not secure entrance until in response to his knock or call the door should be opened by someone within. At night the delay would be increased by the difficulty of arousing the inmates sleeping within the inner chambers. To persons familiar with such experiences, the words of Jesus concerning a higher entrance, "Knock, and it shall be opened unto you" (Matthew 7:7; Luke 12:36), would have a unique force not easy for us to appreciate.